Imagine a male African American baby born in the US in 2012. According to the CDC and the NVSS, that baby would have a life expectancy of 72.3 years. Now imagine that baby ends up living more than 3600 years. Trans folk and other persons, I bring you the Opportunity Rover.
Expected to have a life of 90 Martian days (90 rotations of Mars or about 92 days and 8 hours on earth), the Opportunity Rover has now been performing tasks of exploration and discovery for 5000 Sols – over 14 years and 18 days on Earth (5128.5 days).
This doesn’t mean that NASA was being deceptive in billing this as a 90 Sol mission. Look at the CDC data again. A 100 year old Black man in the USA in 2012 could still expect 2.6 more years of life. The average expectancy includes those short lives ended during infancy 2.2 times as often for Black children as for non-Hispanic white children. In a metaphoric parallel, robotic missions to Mars also die in infancy far too often. So once we had Opportunity safe on the Martian surface, I (and I’m sure many others) expected that odds were better than 50/50 that the 3-month mission would need an extension. But to be perfectly honest, I thought that surviving one Martian winter would be impressive and two would be ultimately, if not immediately, fatal. With a Martian year at 687 days (about 670 Sols), I guessed it’s survivability might be 1500 Sols at the outside, and probably less. 1100-1200 seemed a decent WAG to me.
Spirit ended up double that. Opportunity doubled that again. And now it hits 5000 Sols and is still performing valuable science, including scouting for future missions. It’s hard to believe that human beings, working together, can send 1 tonne packages to another planet. It’s amazing to bear witness to the ongoing success of the Spirit/Opportunity paired mission. I don’t think I’m going to try my hand at estimating Opportunity’s final date of failure. As a Martian actuary, I’m just not that successful.